IRIS BENTLEY yesterday won a victory in her fight to clear the name of her brother Derek - hanged in 1953 for the murder of a policeman - when the Court of Appeal rebuked the Home Office for refusing a posthumous pardon.

In a landmark ruling, which established that the exercise of the Royal Prerogative can be judicially reviewed, the court said it should be possible 'to devise some formula which would amount to a clear acknowledgement that an injustice was done'. The 21-page judgment makes it highly likely that some form of pardon will be given to Derek Bentley. In effect, the judges said that, at the very least, the Home Office should formally acknowledge that it was wrong to hang him.

Miss Bentley, 61, said: 'I have gained a bit of confidence in English justice now.' Michael Howard, the Home Secretary, said: 'I will consider in the light of the judgment what action I should take.'

Bentley was found guilty of murder after his accomplice in a burglary, Christopher Craig, shot a policeman. Convicted on the ground that he encouraged his friend to pull the trigger, Bentley was executed; Craig was reprieved because he was only 16.

Yesterday, Lord Justice Watkins, Lord Justice Neill and Mr Justice Tuckey said there was 'compelling evidence' to suggest that the Home Office had made a mistake when it insisted upon Bentley's hanging.

The judges also criticised Kenneth Clarke, who, as Home Secretary, refused a pardon last October. Mr Clarke had said he could exercise the Royal Prerogative of mercy only when innocence had been proven. That was an error, the court said. It was open to the Home Secretary to grant a posthumous pardon where the sentence, rather than the conviction, had been unjust.

Mr Clarke, now Chancellor, said last night: 'I seriously doubt whether we should entertain old and posthumous cases in this way.'